U.S. patent application number 13/236722 was filed with the patent office on 2012-03-22 for automotive display apparatus.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Masakatsu KINOSHITA, Masahiko Tanaka.
Application Number | 20120069446 13/236722 |
Document ID | / |
Family ID | 45002177 |
Filed Date | 2012-03-22 |
United States Patent
Application |
20120069446 |
Kind Code |
A1 |
KINOSHITA; Masakatsu ; et
al. |
March 22, 2012 |
AUTOMOTIVE DISPLAY APPARATUS
Abstract
According to one embodiment, an automotive display apparatus
includes an image projection unit and a control unit. The image
projection unit is configured to project a light flux including an
image by using a reflecting unit to reflect the light flux. The
control unit is configured to control an operation of the image
projection unit so that the image projection unit moves a
projection region of the light flux by an amount substantially
proportional to (Vc).sup.2.times..delta. from a predetermined
initial position in a horizontal direction orthogonal to an optical
axis of the light flux projected toward the predetermined initial
position, where the Vc is a velocity of a vehicle and the .delta.
is a steering angle of the vehicle.
Inventors: |
KINOSHITA; Masakatsu;
(Kanagawa-ken, JP) ; Tanaka; Masahiko;
(Kanagawa-ken, JP) |
Assignee: |
KABUSHIKI KAISHA TOSHIBA
Tokyo
JP
|
Family ID: |
45002177 |
Appl. No.: |
13/236722 |
Filed: |
September 20, 2011 |
Current U.S.
Class: |
359/630 |
Current CPC
Class: |
G02B 2027/0159 20130101;
G02B 27/01 20130101; G02B 2027/014 20130101; G02B 27/0149
20130101 |
Class at
Publication: |
359/630 |
International
Class: |
G02B 27/01 20060101
G02B027/01 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 22, 2010 |
JP |
2010-211680 |
Claims
1. An automotive display apparatus comprising: an image projection
unit configured to project a light flux including an image by using
a reflecting unit to reflect the light flux; and a control unit
configured to control an operation of the image projection unit so
that the image projection unit moves a projection region of the
light flux by an amount substantially proportional to
(Vc).sup.2.times..delta. from a predetermined initial position in a
horizontal direction orthogonal to an optical axis of the light
flux projected toward the predetermined initial position, where the
Vc is a velocity of a vehicle and the .delta. is a steering angle
of the vehicle.
2. The apparatus according to claim 1, wherein the control unit is
configured to determine the amount substantially proportional to
(Vc).sup.2.times..delta. by a calculation by using the Vc and the
.delta..
3. The apparatus according to claim 1, further comprising an
acceleration meter configured to detect an acceleration in a
horizontal direction orthogonal to a direct advance direction of
the vehicle, the control unit being configured to calculate the
amount substantially proportional to (Vc).sup.2.times..delta. by
using the acceleration.
4. The apparatus according to claim 1, wherein the control unit is
configured to determine the amount substantially proportional to
(Vc).sup.2.times..delta. by using a coefficient defined based on a
human viewer information including at least one selected from a
body weight of a human viewer to view the image, a body height of
the human viewer, a sitting height of the human viewer, an age of
the human viewer, and a setting from the human viewer.
5. The apparatus according to claim 4, further comprising a human
viewer information storage unit configured to store the human
viewer information regarding the human viewer, the control unit
being configured to determine the amount substantially proportional
to (Vc).sup.2.times..delta. by using a coefficient defined based on
the human viewer information stored in the human viewer information
storage unit.
6. The apparatus according to claim 1, wherein the image projection
unit is configured to make a width of the light flux in the initial
position in a horizontal direction orthogonal to a direct advance
direction of the vehicle not more than 75 millimeters.
7. The apparatus according to claim 1, wherein the control unit is
configured to calculate a value proportional to
(Vc).sup.2.times..delta. and to control the image projection unit
to move the projection region when an absolute value of the
calculated value is greater than a predetermined value.
8. The apparatus according to claim 1, wherein the control unit is
configured to make an absolute value of a proportional coefficient
of the amount with respect to the (Vc).sup.2.times..delta. when
increasing the amount greater than an absolute value of the
proportional coefficient when decreasing the amount.
9. The apparatus according to claim 1, wherein the control unit is
configured to control the image projection unit not to operate when
the amount is in a zone predetermined with respect to the
amount.
10. The apparatus according to claim 1, wherein the control unit is
configured to control the image projection unit not to operate when
a value proportional to the (Vc).sup.2.times..delta. is increasing
and within a first zone predetermined with respect to the value and
when the value proportional to the (Vc).sup.2.times..delta. is
decreasing and within a second zone predetermined with respect to
the value, the second zone being different from the first zone.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2010-211680, filed on Sep. 22, 2010; the entire contents of which
are incorporated herein by reference.
FIELD
[0002] Embodiments described herein relate generally to an
automotive display apparatus.
BACKGROUND
[0003] In an automotive head-up display (HUD), light flux including
display information such as vehicle speed, route guidance, etc.,
are reflected by a windshield, etc., to be projected toward a human
viewer. Thereby, the human viewer visually confirms the display
information simultaneously with external environment
information.
[0004] When operating the vehicle, for example, in a curve, the
posture of the human viewer may change from that when travelling
straight. The position of an eye of the human viewer also changes
as the posture changes according to the traveling state. It is
necessary for the light flux to be projected toward the eye even in
the case where the position of the eye changes.
[0005] Conventionally, methods have been considered to adjust the
display position according to, for example, the turning direction
of the vehicle.
[0006] However, conventional methods are insufficient because the
precision of the control of the projection position of the light
flux is low.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic view illustrating the configuration of
an automotive display apparatus according to a first
embodiment;
[0008] FIG. 2 is a graph illustrating experimental results
regarding the travel of the vehicle;
[0009] FIG. 3 is a graph illustrating operation of the automotive
display apparatus according to the first embodiment;
[0010] FIG. 4 is a graph illustrating another operation of the
automotive display apparatus according to the first embodiment;
[0011] FIG. 5 is a graph illustrating another operation of the
automotive display apparatus according to the first embodiment;
[0012] FIG. 6 is a graph illustrating another operation of the
automotive display apparatus according to the first embodiment;
[0013] FIG. 7 is a schematic view illustrating the configuration of
an automotive display apparatus according to a second embodiment;
and
[0014] FIG. 8 is a graph illustrating operations of an automotive
display apparatus according to a third embodiment.
DETAILED DESCRIPTION
[0015] In general, according to one embodiment, an automotive
display apparatus includes an image projection unit and a control
unit. The image projection unit is configured to project a light
flux including an image by using a reflecting unit to reflect the
light flux. The control unit is configured to control an operation
of the image projection unit so that the image projection unit
moves a projection region of the light flux by an amount
substantially proportional to (Vc).sup.2.times..delta. from a
predetermined initial position in a horizontal direction orthogonal
to an optical axis of the light flux projected toward the
predetermined initial position, where the Vc is a velocity of a
vehicle and the .delta. is a steering angle of the vehicle.
[0016] Embodiments will be described hereinafter with reference to
the accompanying drawings.
[0017] In the specification and the drawings of the application,
components similar to those described in regard to a drawing
thereinabove are marked with like reference numerals, and a
detailed description is omitted as appropriate.
First Embodiment
[0018] FIG. 1 is a schematic view illustrating the configuration of
an automotive display apparatus according to a first
embodiment.
[0019] As illustrated in FIG. 1, the automotive display apparatus
10 according to the embodiment is mounted in a vehicle 730. The
vehicle 730 includes any moving body in which a person can ride and
operate such as, for example, a four-wheeled vehicle, a
three-wheeled vehicle, a truck, a bus, etc.
[0020] The automotive display apparatus 10 projects a light flux
112 including an image toward a human viewer 100 riding in the
vehicle 730 by using a reflecting unit 711 to reflect the light
flux 112. The human viewer 100 is a driver capable of operating,
for example, a steering apparatus 731 (handlebars or a steering
wheel) of the vehicle 730.
[0021] The reflecting unit 711 may include, for example, a
combiner.
[0022] The reflecting unit 711 may be, for example, at least a
portion of a windshield unit 710. The windshield unit 710 may
include a windshield of the vehicle 730. The reflecting unit 711 is
provided on, for example, the interior side of the windshield of
the vehicle 730.
[0023] The reflecting unit 711 is provided, for example, in a
surface of the windshield on the interior side of the vehicle 730.
The reflecting unit 711 may be provided apart from the windshield
on the interior side of the vehicle 730. The reflecting unit 711
may be included in the automotive display apparatus 10. The
reflecting unit 711 may be storable in a housing included in the
automotive display apparatus 10.
[0024] The automotive display apparatus 10 includes an image
projection unit 115, an information acquisition unit 210, and a
control unit 250.
[0025] The information acquisition unit 210 acquires vehicle
information s01 including velocity information regarding a velocity
Vc of the vehicle 730 and steering angle information regarding a
steering angle .delta. of the vehicle 730. The information
acquisition unit 210 acquires, for example, the vehicle information
s01 from a vehicle information control unit 730a provided in the
vehicle 730. Other than the velocity information and the steering
angle information, the vehicle information s01 may include any
information regarding the vehicle 730. The velocity information and
the steering angle information may be acquired as a digital signal
or an analog signal. The vehicle information s01 may further
include acceleration information regarding to an acceleration of
the vehicle 730. The automotive display apparatus 10 may further
include an acceleration meter 730b. Description for the
acceleration is provided later.
[0026] The velocity information is information regarding the
velocity Vc and may be, for example, information measured by a
speedometer provided in the vehicle 730. The velocity information
may be a number of rotations of the wheel, etc. For example, the
velocity Vc is derivable based on the number of rotations of the
wheel. Thus, the velocity information includes any information
capable of deriving the velocity Vc.
[0027] The steering angle information is information regarding the
steering angle .delta. and may be, for example, information
measured by a measurement apparatus configured to measure an angle
of the steering apparatus 731. The steering angle information may
include a value measured by an apparatus configured to measure the
state of any mechanism included in the process of changing the
angle of the wheel by, for example, an operation of the steering
apparatus. The steering angle .delta. is derivable based on, for
example, the angle of a gear that controls the angle of the wheel,
etc. Thus, the steering angle information includes any information
capable of deriving the steering angle .delta..
[0028] The image projection unit 115 projects the light flux 112
toward the human viewer 100 by using the reflecting unit 711 to
reflect the light flux 112. The image projection unit 115 includes,
for example, an image data generation unit 130, an image generation
unit 110, and a projection unit 120.
[0029] The image data generation unit 130 generates image data
corresponding to an image including a display object 180 and
supplies the image data to the image generation unit 110.
[0030] The display object 180 is an object provided in the image
presented by the automotive display apparatus 10 to the human
viewer 100. The display object 180 includes, for example,
information regarding operation information of the vehicle 730 in
which the automotive display apparatus 10 is mounted. The display
object 180 may include various content such as arrows illustrating
the velocity and the travel direction of the vehicle 730, the state
of the transmission, etc. The display object 180 may include
information regarding route guidance of the vehicle 730.
[0031] The image generation unit 110 may include, for example, an
optical switch such as a liquid crystal display apparatus (an LCD)
and the like. The image generation unit 110 forms an image on the
screen of the image generation unit 110 based on the supplied image
data from the image data generation unit 130.
[0032] The projection unit 120 may include, for example, various
light sources, lenses, mirrors, and various optical elements
configured to control the divergence angle (the diffusion
angle).
[0033] In the specific example, the projection unit 120 includes a
light source 121, a tapered light guide 122, a light source side
lens 123, an aperture 124, an emerging side lens 125, and an
emerging-side mirror 126.
[0034] The light source 121 produces light used to form the light
flux 112. Along the travel direction of the light used to form the
light flux 112, the tapered light guide 122 is disposed between the
light source 121 and the emerging-side mirror 126, the light source
side lens 123 is disposed between the tapered light guide 122 and
the emerging-side mirror 126, the aperture 124 is disposed between
the light source side lens 123 and the emerging-side mirror 126,
and the emerging side lens 125 is disposed between the aperture 124
and the emerging-side mirror 126.
[0035] In the specific example, the image generation unit 110
(e.g., the LCD) is disposed between the tapered light guide 122 and
the light source side lens 123.
[0036] The light source 121 may include various light sources such
as an LED (Light Emitting Diode), a high pressure mercury lamp, a
halogen lamp, a laser, etc. By using an LED as the light source
121, the power consumption can be reduced; and the apparatus can be
lighter and smaller.
[0037] Various modifications are possible for the configurations of
the image data generation unit 130, the image generation unit 110,
and the projection unit 120. The dispositions of the components
included in the image generation unit 110 and the components
included in the projection unit 120 are arbitrary. For example, the
image generation unit 110 (and the components included therein) may
be inserted between the components included in the projection unit
120.
[0038] For example, the light emitted from the light source 121 is
controlled by the tapered light guide 122 to have a divergence
angle within some range. Then, the light becomes the light flux 112
including the image including the prescribed display object 180 by
passing through the image generation unit 110.
[0039] In the specific example, the emerging-side mirror 126 has a
concave configuration. Thereby, the image of the image information
included in the light flux 112 is enlarged and projected toward the
human viewer 100.
[0040] The light flux 112 is reflected by the emerging-side mirror
126, and subsequently is reflected by the reflecting unit 711 to
reach an eye 101 of the human viewer 100.
[0041] The human viewer 100 perceives an image 181 (a virtual
image) of the display object 180 formed at the position of an image
formation position 181p via the reflecting unit 711. Thus, the
automotive display apparatus 10 can be used as a HUD.
[0042] The emerging-side mirror 126 may be movable. For example,
the light flux 112 may be appropriately projected toward the eye
101 by adjusting the position and/or the angle of the emerging-side
mirror 126 manually or automatically to match the position and/or
the movement of the head 105 of the human viewer 100.
[0043] The image projection unit 115 further includes a drive unit
127. The drive unit 127 includes a motor and the like configured to
change the angle, the position, etc., of the optical element
included in the image projection unit 115. In the specific example,
the drive unit 127 changes the angle, the position, etc., of the
emerging-side mirror 126. The embodiment is not limited thereto;
and the drive unit 127 may change the angle, the position, etc., of
any optical element included in the image projection unit 115. The
emergence direction of the light flux 112 is changed by the angle
and/or the position of the optical element being changed by the
drive unit 127. Thereby, for example, a projection position 113 of
the light flux at the position of the human viewer 100 is
controlled.
[0044] Various modifications other than the examples recited above
are possible for the image projection unit 115.
[0045] The image projection unit 115 of the automotive display
apparatus 10 is provided, for example, in the vehicle 730. The
image projection unit 115 may be provided, for example, in an inner
portion of a dashboard 720 of the vehicle 730 as viewed by the
human viewer 100.
[0046] On the other hand, it is not always necessary for the image
data generation unit 130 to be provided integrally with the image
projection unit 115; and the image data generation unit 130 may be
disposed, for example, not in the interior of the dashboard 720 but
at any location of the vehicle 730. The image data from the image
data generation unit 130 is supplied to the image projection unit
115 (of the image generation unit 110) using a wired or wireless
method of an electrical signal, an optical signal, etc.
[0047] In the automotive display apparatus 10, the human viewer 100
views the image included in the light flux 112 by one eye or by
both eyes.
[0048] For example, in the case of viewing by one eye 101, the
image projection unit 115 projects the light flux 112 toward one of
the eyes of the human viewer 110 and does not project the light
flux 112 toward both of the eyes of the human viewer 100. It is
possible to keep a resynthesis error low by making the human viewer
100 recognize images as different images of a scene in a three
dimension and the image in a two dimension. In such a case, the
light flux 112 is projected toward the one eye 101 and is not
projected toward both eyes by controlling the spread of the light
flux 112 to be continuously not viewed by both eyes. The size of a
projection region 114 of the light flux 112 at the position of the
human viewer 100 is set to be a size that enters the one eye 101
and does not enter both eyes. Because the spacing between the eyes
(the pupils) of the human viewer 100 is, for example, 60
millimeters (mm) to 75 mm, the width of the light flux 112 in the
lateral direction (the width of the projection region 114 in the
lateral direction) at the position of the human viewer 100 is set
to be, for example, not more than 75 mm. Further, this may be set
to be not more than 65 mm and may be set to be not more than 60 mm.
The size of the projection region 114 is controlled, for example,
mainly by the optical element included in the projection unit
120.
[0049] The reflecting unit 711 (e.g., the windshield unit 710) is
disposed at a position having a distance from the human viewer 100
not less than 21.7 cm. Thereby, in the case where the human viewer
100 views the image with the one eye 101, the perceived sense of
depth is increased; and it can be easy for the display object 180
to be perceived at the desired depthward position.
[0050] The image projection unit 115 may project the light flux 112
toward both eyes of the human viewer 100. The human viewer 100 may
view the display object 180 with both eyes.
[0051] The control unit 250 controls the position of the light flux
112 (the projection position 113) at the position of the human
viewer 100 by controlling the image projection unit 115.
[0052] Herein, for convenience of description, the direction from
the rear toward the front of the vehicle 730 is taken as a Z-axis
direction. The direction from the left toward the right of the
vehicle 730 is taken as an X-axis direction. The direction upward
from under the vehicle 730 is taken as a Y-axis direction. The
direction from the left toward the right as viewed from the rear
toward the front of the vehicle 730 is taken as a positive X-axis
direction.
[0053] The control unit 250 controls, for example, the position of
the light flux 112 (the projection position 113) in the X-Y plane
at, for example, the position of the human viewer 100 in the Z-axis
direction. In particular, the position of the light flux 112 along
the X-axis direction is modified.
[0054] For example, the vehicle information s01 or control
information s02 based on the vehicle information from the
information acquisition unit 210 is supplied to the control unit
250. The control unit 250 supplies, for example, a control signal
s03 to the drive unit 127 based on the control information s02.
[0055] The drive unit 127 modifies the projection position 113 by
modifying the angle, the position, etc., of the optical element
(e.g., the emerging-side mirror 126) included in the image
projection unit 115 based on the control signal s03.
[0056] It is not always necessary for the control unit 250 to be
integrally provided with the image projection unit 115; and the
control unit 250 may be disposed at any location of the vehicle
730. The control signal s03 from the control unit 250 is supplied
to the image projection unit 115 using a wired or wireless method
of an electrical signal, an optical signal, etc.
[0057] When changing the position of the light flux 112 (the
projection position 113) at the position of the human viewer 100,
the control unit 250 according to the embodiment changes the
projection position 113 by a distance of
k.times.(Vc).sup.2.times..delta. using the velocity Vc and the
steering angle .delta. acquired by the information acquisition unit
210 and the coefficient k. A movement distance L1 of the projection
position 113 when the projection position 113 is changed may be
k.times.(Vc).sup.2.times..delta.. Here, the movement distance L1 of
the projection position 113 when the projection position 113 is
changed may be k.times.Pr, where a traveling state parameter Pr is
(Vc).sup.2.times..delta..
[0058] For example, the coefficient k may be not less than about
4.times.10.sup.-4 and not more than about 8.times.10.sup.-4 in the
case where, for example, the units of the velocity Vc are km/h
(kilometers per hour) and the units of the steering angle .delta.
are degrees. For example, the movement distance L1 of the
projection position 113 may be not less than 19.2 mm and not less
than 38.4 mm in the case where the velocity Vc is 40 km/h and the
steering angle .delta. is 30 degrees. The coefficient k was
determined experimentally as described below. The coefficient k
changes in the case where the units of the velocity Vc, the
steering angle .delta., and the movement distance L1 are
changed.
[0059] The coefficient k is modifiable based on the specifications
of the vehicle 730 (e.g., the height of the vehicle 730, the
configuration of the seat, etc.), the characteristics and/or the
preferences of the human viewer 100, etc.
[0060] Herein, for example, the travel direction of the vehicle 730
is taken to change to the right when the steering angle .delta. is
positive. The travel direction of the vehicle 730 is taken to
change to the left when the steering angle .delta. is negative.
[0061] The movement direction of the projection position 113 for a
positive steering angle .delta. is the positive X-axis
direction.
[0062] The projection position 113 is moved to the right from the
projection position 113 of the straight travel of the vehicle 730
when the travel direction of the vehicle 730 changes to the right
(e.g., a right curve or when turning right).
[0063] The movement direction of the projection position 113 for a
negative steering angle .delta. is the negative X-axis direction.
The projection position 113 is moved to the left from the
projection position 113 of the straight travel of the vehicle 730
when the travel direction of the vehicle 730 changes to the left
(e.g., a left curve or when turning left).
[0064] Thus, the image can be projected toward the human viewer 100
with high positional precision by controlling the movement distance
L1 of the projection position 113 when the projection position 113
is changed to be k.times.(Vc).sup.2.times..delta..
[0065] An example of the experimental results from which this
configuration was derived will now be described.
[0066] In the experiments described below, images of the human
viewer 100 (the driver) were recorded when the vehicle 730 was
traveling in a left curve; and the position of the eye 101 of the
human viewer 100 was measured from the results.
[0067] FIG. 2 is a graph illustrating experimental results
regarding the travel of the vehicle.
[0068] In FIG. 2, the horizontal axis is the traveling state
parameter Pr. The vertical axis is the position of the eye 101 and
is a movement distance L01 from a reference position.
[0069] This result is an example in which the velocity Vc is
substantially constant and the steering angle .delta. changes.
[0070] As illustrated in FIG. 2, it was learned that the movement
distance L01 of the eye 101 changes substantially linearly with the
traveling state parameter Pr. The movement direction of the eye 101
in this case was the negative X-axis direction (i.e., to the
left).
[0071] It can be seen from FIG. 2 that the movement distance L01 of
the eye 101 differs between when the absolute value of the
traveling state parameter Pr is increasing (when entering a curve)
and when the absolute value of the traveling state parameter Pr is
decreasing (when exiting the curve). The movement distance L01 of
the eye 101 when the absolute value of the traveling state
parameter Pr is increasing is greater than the movement distance
L01 of the eye 101 when the absolute value of the traveling state
parameter Pr is decreasing.
[0072] Although this experimental example is the case of a left
curve, similar results were obtained for the case of a right curve.
However, the movement direction of the eye 101 in the case of the
right curve was the positive X-axis direction, which was the
reverse of the case of the left curve.
[0073] Thus, the head 105 (the eye 101) of the human viewer 100
moves to the left in the left curve. It is conceivable that this is
caused by an acceleration to the right being applied to the human
viewer 100 in the left curve and the human viewer 100 moving
(tilting) the head 105 to the left as an action against this
acceleration. Conversely, the head 105 (the eye 101) of the human
viewer 100 moves to the right in the right curve. It is conceivable
that this is caused by an acceleration to the left being applied to
the human viewer 100 in the right curve and the human viewer 100
moving (tilting) the head 105 to the right as an action against
this acceleration.
[0074] From this result, the light flux 112 can be projected toward
the eye 101 with good precision by controlling the position of the
light flux 112 (the projection position 113) at the position of the
human viewer 100 based on the traveling state parameter Pr to
correspond to the change of the travel direction of the vehicle 730
and the accompanying change of the position of the head 105
(specifically, the eye 101) of the human viewer 100.
[0075] FIG. 3 is a graph illustrating operation of the automotive
display apparatus according to the first embodiment.
[0076] In FIG. 3, the horizontal axis is the traveling state
parameter Pr; and the vertical axis is the movement distance L1
from the reference position (a predetermined initial position) of
the projection position 113 of the light flux 112 at the position
of the human viewer 100. A positive traveling state parameter Pr
corresponds to the case where the travel direction changes to the
right (e.g., a right curve, a right turn, etc.); and a negative
traveling state parameter Pr corresponds to the case where the
travel direction changes to the left (e.g., a left curve, a left
turn, etc.).
[0077] In the automotive display apparatus 10 according to the
embodiment as illustrated in FIG. 3, the movement distance L1 of
the projection position 113 of the light flux 112 is substantially
proportional to the traveling state parameter Pr.
[0078] In other words, the control unit 250 changes the projection
position 113 by a distance of k.times.(Vc).sup.2.times..delta.
using the velocity Vc and the steering angle .delta. acquired by
the information acquisition unit 210 and the coefficient k when
changing the position of the light flux 112 (the projection
position 113) at the position of the human viewer 100. The control
unit 250 is configured to control the operation of the image
projection unit 115 so that the image projection unit 115 moves the
projection region 114 of the light flux 112 by an amount (the
movement distance L1), which is substantially proportional to
(Vc).sup.2.times..delta. in the horizontal direction. The
horizontal direction is orthogonal to an optical axis 114a of the
light flux projected toward the predetermined initial position. For
example, the control unit 250 is configured to determine the amount
(the movement distance L1) substantially proportional to
(Vc).sup.2.times..delta. by a calculation by using the Vc and the
.delta..
[0079] The movement distance L1 is positive (the direction from the
left of the vehicle 730 to the right) when the traveling state
parameter Pr is positive (e.g., the direction from the left of the
vehicle 730 to the right); and the movement distance L1 is negative
(the direction from the right of the vehicle 730 to the left) when
the traveling state parameter Pr is negative (e.g., the direction
from the right of the vehicle 730 to the left).
[0080] Thereby, the image can be projected toward the human viewer
100 with high positional precision.
[0081] In particular, in the automotive display apparatus 10, the
width of the light flux 112 is set to be narrow in the case where
the light flux 112 is viewed using the one eye 101. In such a
monocular HUD, the precision of the control of the projection
position 113 of the light flux 112 by conventional methods is low
and impractical. Thus, the embodiment is an approach to solve new
problems occurring in the monocular HUD.
[0082] In other words, in the automotive display apparatus 10, the
width (the width in the lateral direction) of the projection region
114 of the light flux 112 at the position of the human viewer 100
is set to be, for example, not more than 75 mm; and the projection
position 113 of the light flux 112 having such a narrow width is
controlled as recited above. Thus, the effects of the embodiment
are realized particularly markedly in the case where the light flux
112 has a narrow width.
[0083] The embodiment is advantageous in that high positional
precision can be determined by a simple calculation based on the
traveling state parameter Pr (i.e., (Vc).sup.2.times..delta.) by
changing the movement distance L1 of the light flux 112 linearly
with the traveling state parameter Pr.
[0084] However, it is unnecessary for the movement distance L1 of
the light flux 112 to be strictly proportional to
(Vc).sup.2.times..delta.; and an error may be included in the
movement distance L1. For example, the movement distance L1 may be
set to be within a prescribed range centered on
k.times.(Vc).sup.2.times..delta..
[0085] FIG. 4 is a graph illustrating another operation of the
automotive display apparatus according to the first embodiment.
[0086] In FIG. 4, the horizontal axis is the traveling state
parameter Pr; and the vertical axis is the movement distance L1 of
the projection position 113 of the light flux 112 at the position
of the human viewer 100.
[0087] As illustrated in FIG. 4, in a control method P1 in which
the movement distance L1 of the projection position 113 is set to
be proportional to (Vc).sup.2.times..delta., the movement distance
L1 can be controlled with a certain error. An example of the error
is shown in FIG. 4 as an error range P2. The error range is, for
example, a range of plus or minus x % of
k.times.(Vc).sup.2.times..delta.. The movement distance L1 of the
light flux 112 is controlled to be, for example, plus or minus 20%
of k.times.(Vc).sup.2.times..delta. (i.e., x=20).
[0088] For example, as in a control method P3, a rate of the change
of the movement distance L1 with respect to
(Vc).sup.2.times..delta. may be changed within the error range P2
(for example, plus or minus 20% of
k.times.(Vc).sup.2.times..delta.). The movement distance L1 of the
light flux 112 may be controlled to have a curved configuration (a
zigzagging configuration) that changes within a range of the plus
or minus 20% of k.times.(Vc).sup.2.times..delta..
[0089] However, as described in regard to FIG. 2, the movement
distance L1 of the light flux 112 is controlled to be substantially
proportional (e.g., not more than plus or minus 20%) to the
traveling state parameter Pr (i.e., (Vc).sup.2.times..delta.) to
match the characteristic of the movement of the eye 101 of the
human viewer 100.
[0090] Here, as described in regard to FIG. 2, the movement
distance L01 of the eye 101 when the absolute value of the
traveling state parameter Pr is increasing is greater than the
movement distance L01 when decreasing.
[0091] FIG. 5 is a graph illustrating another operation of the
automotive display apparatus according to the first embodiment.
[0092] In FIG. 5, the horizontal axis is the traveling state
parameter Pr; and the vertical axis is the movement distance L1 of
the projection position 113 of the light flux 112 at the position
of the human viewer 100.
[0093] As illustrated in FIG. 5, a gradient of the straight line of
the movement distance L1 with respect to the traveling state
parameter Pr in increasing the movement distance L1 is larger than
that in decreasing the movement distance L1. In other words, an
absolute value of a proportional coefficient (the coefficient k) of
the movement distance L1 with respect to the value of
(Vc).sup.2.times..delta. in increasing the absolute value of the
movement distance L1 is larger than that in decreasing the absolute
value of the movement distance L1.
[0094] For the same traveling state parameter Pr, the absolute
value of the movement distance L1 of the projection position 113 of
the light flux 112 when the absolute value of the traveling state
parameter Pr is increasing may be set to be greater than the
absolute value of the movement distance L1 when the absolute value
of the traveling state parameter Pr is decreasing.
[0095] In other words, the coefficient k (the absolute value
thereof) when the absolute value of the traveling state parameter
Pr ((Vc).sup.2.times..delta.) is increasing is set to be greater
than the coefficient k (the absolute value thereof) when the
absolute value of the traveling state parameter Pr
((Vc).sup.2.times..delta.) is decreasing.
[0096] For example, a first coefficient k1 when the traveling state
parameter Pr is positive and the traveling state parameter Pr is
increasing is set to be greater than a second coefficient k2 when
the traveling state parameter Pr is positive and the traveling
state parameter Pr is decreasing.
[0097] For example, a third coefficient k3 when the traveling state
parameter Pr is negative and the absolute value of the traveling
state parameter Pr is increasing is set to be greater than a fourth
coefficient k4 when the traveling state parameter Pr is negative
and the absolute value of the traveling state parameter Pr is
decreasing.
[0098] Thereby, it is possible to control the projection position
113 of the light flux 112 to better match the characteristic
regarding the movement of the eye 101.
[0099] FIG. 6 is a graph illustrating another operation of the
automotive display apparatus according to the first embodiment.
[0100] In FIG. 6, the horizontal axis is the traveling state
parameter Pr; and the vertical axis is the movement distance L1 of
the projection position 113 of the light flux 112 at the position
of the human viewer 100.
[0101] As illustrated in FIG. 6, in this operation, regarding to
the traveling state parameter Pr, a first threshold value Pr1
(e.g., a positive threshold value) and a second threshold value Pr2
(e.g., a negative threshold value) are determined. When the
traveling state parameter Pr is not larger than the first threshold
value Pr1 and not smaller than the second threshold value Pr2, the
movement distance L1 is zero. When the traveling state parameter Pr
is larger than the first threshold value Pr1, the movement distance
L1 is a value that satisfies the relation of L1=k.times.Pr. When
the traveling state parameter Pr is negative and is smaller than
the second threshold value Pr2, the movement distance L1 is a value
that satisfies the relation of L1=k.times.Pr. When the traveling
state parameter Pr is the first threshold or the second threshold
value Pr2, the absolute value of the movement distance L1 is
increased in stepwise.
[0102] In this example, the control unit starts the control to
interlock the projection position 113 with the movement of the eye
101 by moving the projection position 113 of the light flux 112
when the absolute value of the traveling state parameter Pr exceeds
a prescribed threshold value. The control unit 250 does not move
the projection position 113 when the absolute value of the
traveling state parameter Pr is not more than the threshold
value.
[0103] For example, play (an insensitive region) is provided in the
steering apparatus 731 of the vehicle 730. Therefore, there are
cases where it is unnecessary to modify the projection position 113
in the range where the steering angle .delta. is not more than the
prescribed angle.
[0104] The first threshold value Pr1 (e.g., the positive side) and
the second threshold value Pr2 (e.g., the negative side)
corresponding to the angle of the play of the steering apparatus
731 are predetermined for the traveling state parameter Pr. The
control unit 250 performs a process in which the projection
position 113 is not moved in the case where the absolute value of
the obtained traveling state parameter Pr is not more than the
absolute values of the first threshold value Pr1 and the second
threshold value Pr2; and the projection position 113 is moved when
the absolute values of the first threshold value Pr1 and the second
threshold value Pr2 are exceeded.
[0105] The control unit 250 changes the position of the light flux
112 (the projection position 113) when the absolute value of
k.times.(Vc).sup.2.times..delta. is greater than the predetermined
value and does not change the projection position 113 when the
absolute value is not greater than the predetermined value.
[0106] Thereby, the image can be projected toward the human viewer
with little incongruity and high positional precision.
Second Embodiment
[0107] FIG. 7 is a schematic view illustrating the configuration of
an automotive display apparatus according to a second
embodiment.
[0108] The automotive display apparatus 20 according to the
embodiment includes the image projection unit 115, the information
acquisition unit 210, and the control unit 250 described above. The
configurations thereof are similar to those of the automotive
display apparatus 10 and a description is therefore omitted.
[0109] In the embodiment, the information acquisition unit 210
further acquires human viewer information including at least one
selected from the body weight of the human viewer 100, the body
height of the human viewer 100, the sitting height of the human
viewer 100, the age of the human viewer 100, and a setting from the
human viewer 100. The setting from the human viewer 100 is set by
the human viewer 100 according to personal preferences
(requirements) and is a setting that may be used to increase or
decrease the coefficient k. The human viewer information may
further include the gender of the human viewer.
[0110] For example, the user of the vehicle 730 inputs human viewer
information such as that recited above; and the information
acquisition unit 210 acquires the input human viewer information
from an input unit 230 connected to the automotive display
apparatus 10. The configuration of the input unit 230 recited above
is arbitrary. The input unit 230 may be included in, for example, a
CID (central information display) and the like. The input unit 230
may include any input device provided in the vehicle 730. The input
unit 230 may be included in the automotive display apparatus
20.
[0111] The coefficient k can be defined based on the human viewer
information acquired by the information acquisition unit 210. In
other words, the coefficient k is modifiable based on the human
viewer information.
[0112] It was learned that even for the same traveling state
parameter Pr, the movement distance L01 of the eye 101 differs
according to the characteristics of the human viewer 100 (e.g., the
body weight of the human viewer 100, the body height of the human
viewer 100, the sitting height of the human viewer 100, the age of
the human viewer 100, individual differences of the human viewer
100, etc.). Therefore, the projection position 113 of the light
flux 112 can be matched with higher precision to the position of
the eye 101 of the human viewer 100 by setting the coefficient k
based on the human viewer information regarding the human viewer
100.
[0113] In particular, it is desirable for the coefficient k to be
adjustable according to the requirements of the human viewer 100.
For example, the coefficient k is set to match the specifications
of the vehicle 730 when, for example, the automotive display
apparatus 10 is mounted in the vehicle 730 and the user starts to
use the automotive display apparatus 10. Thereafter, as the user
starts to use the automotive display apparatus 10, there may be
cases where the correspondence between the characteristic of the
movement distance L01 of the eye 101 and the characteristic of the
movement distance L1 of the projection position 113 using the set
coefficient k is low due to the characteristics of the user (habits
when operating, etc.). In such a case, the ease of use can be
better by the user (the human viewer 100) setting the coefficient k
to match the characteristics of the user.
[0114] The automotive display apparatus 20 may further include a
human viewer information storage unit 240. The human viewer
information storage unit 240 stores the human viewer information
regarding the human viewer 100. The coefficient k is defined based
on the human viewer information stored in the human viewer
information storage unit 240. The coefficient k is modifiable based
on the human viewer information.
[0115] It is complicated to input the human viewer information each
time the automotive display apparatus 20 is used. Better
convenience is provided by storing the human viewer information
inputted to the information acquisition unit 210 in the human
viewer information storage unit 240 and by extracting the human
viewer information from the human viewer information storage unit
240 when necessary.
[0116] In particular, better convenience is provided by storing the
human viewer information of multiple users in the case where the
multiple users take turns using the automotive display apparatus
20.
Third Embodiment
[0117] FIG. 8 is a graph illustrating operation of an automatic
display apparatus according to a third embodiment.
[0118] As shown in FIG. 8, in this example, the movement distance
L1 of the projection position 113 changes in stepwise in response
to the change of value of the traveling state parameter Pr
(=(Vc).sup.2.times..delta.). In other words, a plurality of zones
are provided to the calculated values of Pr. For example, in
increasing the movement distance L1, a first to a fifth zone I1 to
I5 are predetermined. In decreasing the movement distance L1, a
first to a fifth zone D1 to D5 are predetermined. In this example,
the first to the fifth zone D1 to D5 are different from the first
to the fifth zone I1 to I5, respectively. The embodiment is not
limited thereto, and the first to the fifth zone D1 to D5 may be
same as the first to the fifth zone I1 to I5, respectively. A
number of the zone is not limited to five and arbitrary.
[0119] In this example, the movement distance L1 is zero in the
case of the first zone I1. In the case of the second zone I2, the
movement distance L1 is a constant value (20 mm in this example)
which is larger than zero. In the case of the third zone I3, the
movement distance L1 is another constant value (40 mm in this
example) which is larger than that for the second zone. In the same
way, the movement distance L1 is changed according to the zones. At
the boundary (the threshold) between the zones, the movement
distance L1 is changed in stepwise.
[0120] For example, in a computer provided in the control unit 250,
the obtained values of the traveling state parameter Pr are
compared with the plurality of threshold values. The movement
distance L1 is determined based on the result. The movement
distance L1 is set as discrete values. At this time, as illustrated
in FIG. 8, the whole relationship between the traveling state
parameter Pr and the movement distance L1 is represented by
L1=k.times.Pr.
[0121] In this example, a change width of the movement distance L1
is 20 mm. However, the embodiment is not limited thereto, and the
change width of the movement distance L1 is arbitrary. For example,
a stepping motor or the like is used for the drive unit 127. More
practical control is allowed by the movement distance L1 being
changed in stepwise. Thus, the control unit 250 performs to control
the image projection unit 115 not to operate in a zone
predetermined with respect to the movement distance L1. The zone
may be changed according to the purpose or the intention of the
control design. In the examples recited above, the zones are set to
obtain the effect described with respect to the examples.
[0122] In the example shown in FIG. 8, the first to the fifth zone
D1 to D5 are different from the first to the fifth zone I1 to I5,
respectively. In other words, the hysteresis characteristics are
introduced into the control of the movement distance L1. For
example, even if the vehicle 730 is turning around to a given
direction on the way of curve, the steering angle .delta. may
repeatedly change slightly. In this case use of the hysteresis
characteristics allows the practical control.
[0123] In the automotive display apparatus according to the
embodiment, for example, before starting to operate the vehicle,
the projection position 113 of the light flux 112 is initialized.
In the initialization, for example, a center position of the
projection region 114 of the light flux 112 is set to a position of
the one eye 101 of the human viewer 100. For example, the control
unit 250 determines the movement distance L1 proportional to
(Vc).sup.2.times..delta. by a calculation by using the Vc and the
.delta. during the operation. When the control unit 250 controls
the projection unit 115 to move the projection region 114, the
control unit 250 makes the projection region 114 of the light flux
112 move by the determined movement distance L1 from the initial
position. Thereby, even when the position of the eye 101 of the
human viewer 100 on the curve or the like, the light flux 112 can
be incident to the intended one eye 101.
[0124] However, the embodiment is not limited thereto. For example,
acceleration may be used to determine the movement distance L1
proportional to (Vc).sup.2.times..delta.
Fourth Embodiment
[0125] In the fourth embodiment, the control unit 250 determines
the movement distance L1 by using the acceleration in the lateral
direction (horizontal direction). The value of Pr
((Vc).sup.2.times..delta.) is proportional to a centrifugal force
when the vehicle 730 makes a curve. The centrifugal force is
expressed by mass.times.(velocity).sup.2/radius of gyration. The
radius of gyration is substantially proportional to
wheelbase/steering angle. Thus, the centrifugal force is
proportional to steering angle.times.(velocity).sup.2. The
centrifugal force applied to the driver (human viewer 100) in the
lateral direction is proportional to the acceleration. Therefore,
by using the acceleration in the lateral direction, the movement
distance L1 proportional to (Vc).sup.2.times..delta. can be
determined.
[0126] The acceleration is, for example, acquired by an
acceleration meter 730b or the like provided in the vehicle 730.
When the travel direction of the vehicle 730 changes to the right,
the centrifugal force is applied in the left direction, and when
the travel direction of the vehicle 730 changes to the left, the
centrifugal force is applied in the right direction. Therefore, the
direction of the acceleration Ac along the X-axis determined by the
acceleration meter 730b is reverse to the direction of the change
of the direction of the vehicle 730. At this time, for example, a
negative value is used for the coefficient k, and thus the movement
direction of the projection position 113 can be coincided with the
movement direction of the eye 101. Moreover, for example, the
polarity of the acceleration is reversed, and thus the movement
direction of the projection position 113 can be coincided with the
movement direction of the eye 101.
[0127] In using the acceleration as well, the gradient of the
straight line of the movement distance L1 with respect to a value
(the acceleration) proportional to (Vc).sup.2.times..delta. in
increasing the movement distance L1 may be larger than that in
decreasing the movement distance L1. The control unit 250 may
perform a control to move the projection region 114 when the
absolute value of the acceleration is greater than a predetermined
value and not to move the projection region 114 when the absolute
value is not greater than the predetermined value. The control unit
250 may determine the movement distance L1 according to zones
predetermined with respect to the acceleration. In this case, the
zones in increasing the movement distance L1 may be different from
the zones in decreasing movement distance L1.
[0128] According to the embodiment, an automotive display apparatus
that can project an image toward a human viewer with high
positional precision is provided.
[0129] Hereinabove, embodiments are described with reference to
specific examples. However, the embodiments are not limited to
these specific examples. For example, one skilled in the art may
similarly practice the embodiments by appropriately selecting
specific configurations of components included in automotive
display apparatuses such as image projection units, information
acquisition units, control units, image data generation units,
image generation units, projection units, etc., from known art.
Such practice is included in the scope of the embodiments to the
extent that similar effects are obtained.
[0130] Further, any two or more components of the specific examples
may be combined within the extent of technical feasibility and are
included in the scope of the embodiments to the extent that the
spirit of the embodiments is included.
[0131] Moreover, all automotive display apparatuses practicable by
an appropriate design modification by one skilled in the art based
on the automotive display apparatuses described above as
embodiments also are within the scope of the embodiments to the
extent that the spirit of the embodiments is included.
[0132] Various other variations and modifications can be conceived
by those skilled in the art within the spirit of the invention, and
it is understood that such variations and modifications are also
encompassed within the scope of the invention.
[0133] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
invention.
* * * * *